In the handling and storage of thin wall, high pressure, fire hose, which usually does not have any wire mesh reinforcing layer, it has been found that with ordinary hose couplings, the drawing of one length of hose over another may cause the sharp edges of the coupling or its bolts and nuts to cut and fracture the hose. Sometimes such hose is stored, or carried in stacks four or five lengths deep so that such dragging and cutting, in unloading the hose, causes considerable damage. On fire trucks, the length of such thin-walled hose may be one hundred feet or more, with one thousand feet of such lengths being carried and stacked on the truck. Thus, a sharp edge on one of the hose couplings can be dragged one hundred feet on the outside surface of another length to scratch it, or cut it, and cause a leak at the most disadvantageous time.
Exemplary of the type of hose couplings now in use and which have hose clamps on the nipples of the hose couplings which include either sharp pointed clamping ribs and grooves or protruding clamp flanges, bolt heads or nuts with sharp edges, or corners, are the following U.S. patents. U.S. Pat. No. 3,249,371, Peterman, May 3, 1966; U.S. Pat. No. 3,257,132, Lyons, Jun. 21, 1966; U.S. Pat. No. 3,432,190, Kunz, Mar. 11, 1969; U.S. Pat. No. 3,495,855, Currie, Feb. 17, 1970;
In each of these patents the split annular hose clamps are of greater diameter than the diameter of the clamp, there are projecting sharp edged attachment flanges protruding from the clamp halves and there are at least one pair, and sometimes two pairs of sharp cornered, hexagonal, bolt heads or nuts projecting beyond the flanges.